Band saw apparatus



Feb; 18, 1947. J. HAJEK BAND 'SAW APPARATUS Filed Spt. 24, 1945 2 Sheets-Sheet 2 I z ll. f

` Patented Feb. 18,

. e 12 Claims.

My invention'relates to band saws, and consists in new andusetui'improvements in the same'. In the band saw. art an endless sawbandis being mounted on two spaced apart flight-reversing pulleys, atleast one of which is power ro tated,- and opposed pairs of pulleys orrollers are on the same as thevoperation proceeds. u

Means are provided for. regulating` the speed employed to guide andmaintain the two flights of i the sawin sliding contact to obtaina'single-cut with a narrow kerf.

In the present practice a machine !ram is employed upon which both setsof .pulleys are mounted, and a work-table carried by the :rame

' is used for supporting the work-piece, theworkpiece being shifted onthe table by the operator to direct the'cut along the selected path.

Thus, in the present practice, the path of the r out is limited by theclearance afforded 'by the v frame and 'the table for the' movement ofthe work-piece. Where the work-piece' is of large area and the selectedpath for the cut is extensive or irregular, it is impossible tocomplete'the operation unless the work piece is removed from the tableand reset thereon at more or less fre-'` Again, where the work-piece is25` quent intervals. heavy, it is difficult either to shift thework-piece 'relative to the table, as the operation progresses, or tomove it with sufilcient accuracy satisfactory results. v

The principal object which I have in view is the provision of meanswhereby, notwithstanding the area or weight or size of the work-piece,or the irregularity' or changes of direction of the selected path of thecut, the latter may be .easily and accurated accomplished. I attain thispurpose by so mounting the saw that it ismoved by the operator relativeto the work-piece which' remains stationary. i

Again I so mount the saw that it is Suspended entirely from above, theupper pulieys being sup ported above the work-piece, and the lowerpulleys being' Suspended beneath the work-piece by the saw-band whichruns about the same.

To provide the proper fiexibility in the moveto obtain clples of thepresent invention,

concealed; i V v u Fle. 2 is a sectional view taken along the dotted 'iBANDSAWAPPARATUS e Joseph Hajek, Mars, Pa.

Application September 24. 1945.' Serial 8l204 (c. na-21) and its supportas a which may be readily mounted on the work-piece itself, and ;may beremoved therefrom or shifted oftravel of the band saw.

other objects in view and other improvements A in structure. andarrangement'of parts will appear from the following description,

In the accompanying drawings wherein illustrated a pratical embodimentof the Flg. 1 a. .front elevation of the assembled band saw `mechanism,the front walls of the upper and' lower 'housings being partially brokenaway to expose' new parts line 2--2 in Figd;

. ngga* 'is a partia! 'view showing the rear face 'of theupperiiight-reversing pulley and the conthe same at difierentspeeds, theremovable rear 4' 'wall of the upper housing being omitted;

ment of the saw band to enableit to accurately follow the selected pathof cut, I support the upper set of pulieys from a stationary support bymeans of a jointed arm structure so that the operator may 'move andguide the saw band aocurately along the selected path.

Again I so construct the jointed arm structure centric' ring gearsmounted thereon for driving Fig. 4 is a similarview 'but with the rearwall in place to show the several positions in which the motor may bemounted to provide for changes in speed;

Fig. 5 is a' cross-sectional view, the dotted line '5-5 in Fig. 1 andshowing the in place;

method of detachably mounting the guide-blocks Fig. 6 is a view in planof the jointed arm from which the saw assembly is supported from above.

Reierring to the drawings, I and 2 indicate the upper and lower housingsin which are journaled the upper and lower flightreversing pulleys 3 and4, respectively. 5 indicates the continuous or. endless band saw havinga series of cutting teeth along' one edge of the same. The band saw ismounted on and runs about both the upper and lower pulieys, and itsflights or intermediate straight portions between thetwo pulleys aredirected into surface contact relation by means of the opposed .pairs ofpulleys 6 and l, which pulleys are also journaled by their axles betweenthe side walls of the housings I and 2 respectively. At the lower end ofthe upper housing I and the upper'end of the lower housing 2,' the edgewalls of the housings converge to form the vertiportable unitaryassembly' I i have prin- I which otherwise would be taken along g callydisposed open ended rectangular sockets 3 having their front wallsprovided with vertical slots 3 to provide clearance for the toothededges of the oppositely traveling flights of the saw band 5 io indicatesthree-sided carriers vertically slidable in the sockets 8 and Secured atthe desired elevation ,by any convenient means, such, for

instance, as the setscrews IL' The 'interior side walls of the carriersn are provided with seats in which are mounted the' opposed guide blccks!2, which blocks are spaced apartsuinciently to provide an open slot inwhich the flights are held in sliding surface contact. !3 indicates aThe blocks l2 and l3 preferably are formed of V some hard wear-resistingmetal alloy, and they may be brazed or otherwise held in place in 'thecarrier. The guide slot mechanism may readilybe removed from andreplaced in the sockets.

'The carriers are vertically adjustable in the e sockets so that theguides may be positioned' closely to the upper and lower surfaces of theworkepiece N, the thickness of which varies for difl'erent .jobs.

The ,upper flight-reversing pulley 3 is powerrotated to drivethe 'sawband, andpreferablyprovision is made for imparting 'various' speeds oftravel thereto, depending 'upon the material of the work-piece to be"cut, hard materials such as high carbon and like steels requiring lowerspeeds than those practice! in `softer materials such as aluminum vorplyboard. i

Thua, as indicated in Fig. 3.1 provide the rear face of the uppernight-'reversing pulley 3 with a plurality oi' concentrically positionedring gears, shown-as three'in number and indicated as IS. IS and IT'respectively, thereby 'providing for three v speeds 'of travel tor 'thesaw band I.

The rear wall 'I: oi' the upper housing may be in the form of aremo'vable lid detachably held in position as by cap screws' s, and saidlid is providedwith a plura'lity 1' porte 20, '2I and 22, equal innumber 'to that of the ring gears and so positioned that when thehearing collar of a portable electric motor 23 is-inSerted into thetical edges.

assembly is suspended is itself Suspended !rom the free end of a jointedarm structure, thus providing free movement ofthe saw assenbly in makingeither a straight, a curved or a tortuous cut in the workpiece !4. Thisjointed arm structure advantageously may be of the following character.

3| is a bracket from the outer or free end of which the swivel mechanism24 is Suspended. This bracket is preferably substantially of thetriangular shape illustrated to provide clearance for the saw assembly,and it is provided at its rear or vertical edge with a pair of outwardlyprojecting upper and lower hinge lugs 32 having aligned bolt holes.

33 indicates a wing plate having parallel ver- The outer edge, the leftin Fig. 1, is provided with a vertical tubular sleeve 31 of properlength to be inserted between the lugs porting the wingplate on thepost.

The post 38 may be a permanent element in 'tial vacuum necessary. willbe firmly attac'hed to the work-piece so as to remain under load in itsvertical position.

proper port a spur pinion on 'the end of the 'motor shaft will mesh withthe corresponding ring gear carried bythe tflight-reversing pulley 3.'Any suitablemeans may be provided 'to lock the motor e temporarily inplace.

The saw assembly is i supported irom 'above by :means 'oi' ;the .upperhousing l' which is sus pended by a swivel bolt mechanism '24 from' thefree end of a jointed ami' structure later tobe described. i V

Suspended 'by means of a swivel mechanism 25 'from the :lower end of thelower housing 2 is a 'winch 26 'provided with a ratchet 21, and `theprotruding'end of'the winch shaft is'squared for the application of'acrank 2.8 or other tool.

19 indicates a cable woundaboutthe winch and provided at itsiree endwith a hook to be attac'hed to a weight which isjthus Suspended from thelower housing and exerts suflicient tension on the band saw to holditiproperlyaligned. The weight may 'be changed to provide the requiredtension. I

The -swivel mechanism 24, from which the saw Thus I close the lower endof the post 39 by means of the threaded plate 40 and screw the threadedlower 'end'of the post into the central opening of the base plate M.domed substantially as shown having an annular outer edge which fltsflat on the surface of the work piece. An annular skirt 42 of' rubber orsimilar flexible material encircles the outer wall of the base and isheld thereto as by the metal band 43. The lower edge of the skirt 42 isbeveled to fit flat on' the 'surface of the work-piece and seal thelower edge of the domed base against the inward leakage of air.

To strengthen the base plate I prefer to provide it with one or moreannular internal ribs '44 which 'are provided with perforations for thepassage of air therethrough.

Any suitable means are provided for exhaust-` ing the air from theinterier of the domed base,

such as the host 45 connected to a port in the upper wall of the baseplate and at its other end to a suction apparatus by means of which thenecessary degree of partial vacuum may be maintained in the interior ofthe base plate.

When the posthas been placed in proper position on the work-piecesuction is applied to provide the necessary grip to exhaust the air andcause adhesion of the base plate to the work.

I also provide the base plate with a second port provided with a valve.43 which .may be opened to admit air to the base plate and release thepost The base ll is position to engage the work and support the sawassembly in position. I provide the lower end of the leg with a rollerso that the saw assembly may be easily shifted on the work-piece.

The advantages of 'my present invention are numerous, as will be evidentto one skilled in the art. Among them are the following.

My invention makes possible the cutting of any selected design orcontour of path in a work-piece of any dimension, such as a sheet orplate of steel, aluminum or any other character of metal or plyboard orany other materialgand this operation may be accomplished with greataccuracy and speed, inasmuch as the work-piece may remain stationary andthe saw assembly may be moved as required.

The workman by seizing the upper guidelsocket may easily direct the kerfin the material of the work-piece to provide the proper direction 'ofcut.

The upper and lower housings, pulleys and guide blocks are preferablyidentical, and thus the manufacturing costs are reduced. The housingsand pulleys advantageously may be made of aluminum, magnesium or otherlight material,-

and in the case of small assembl'ies may be stampings.

By means of the plurality of ring gears concentrically mounted on theupper !light-reversing pulley I am enabled to vary the rotative powerexerted on the pulley, and where a constant speed motor is employed Imay thus change the speed of the saw to suit the character of thework-piece. Again in case a variable speed motor is used by meshing itsspur gear with the proper ring gear I can obtain a wide range'oi' speedselection.

By the use of a post or supporting member which may be temporarilymounted at any convenient location, the entire saw' assembly is capabl'e of being brought into the proper relation to the work-piece, andthe entire assembly may l be supported on the work-piece and shiftedintodifferent positions thereon as may be' desired. This portability of thesaw assembly relative to the work-piece enables me to reduce the sizeand length of the jointed arm which would be impossible wer the assemblysupported from a fixed position. It is to be noted that a, relativelyshort arm would be less liable to vibration and swaying movements. V

The flights of the band saw moving in opposite directions and insli'ding contact balance each other and guide blocks may be adjusted toclose proxlmity to the upper and lower surfaces of the work-piece thusholding the cut accurately in its path.

I claim: v

1. In saw apparatus, the combination of a band saw, an upperflight-reversing pulley over which the saw runs and by which the saw isSuspended,

means for imparting 'rotary motion to said pulley,

a. lower fiight-reversing pulley about which the saw runs and which isSuspended entirely by the saw, and means for causing the 'fliehtportions of the saw intermediate ofthe pulleys to travel 'in slidingsurface contact to cut". a single kerr in a work-piece.` i i 2. In sawapparat'us, the combination of' a band saw, an upperfiight-reversingpulley over which the saw runs and which the sawis suspended, swivel'meansfor suspending said pulley from above, means forimparting rotary' motion to said pulleyxa lower fiight-reversing pulleyabout which thesaw runs and which is Suspended entirelyby the saw,*andmeans for causing the flightportion of the saw'to travel in slidingcontact with each other to cut a single kerr in a work-piece.

3. The structure of claim 1 characterized by *the provision of means toregulate the tension exerted on the flights of' the saw.

4. The structure of claim 2 characterized by the provision of means toregulate the tension exerted on the flights of the saw.

5. The structure of claim 1 characterized by the provision of means forshifting the upper pulle in a plane transverse to that of the flights ofthe saw to vary the direction of the path of I the cut in a work-piece.

6. The structure of claim 2 characterized by the provision of means forshifting the upper pulley in a plane transvcrse to that of the flightsof the saw to vary the direction of the path of the cut in a work-piece.

7. In sawing apparatus, the combination of a band saw, an upperfiight-reversing pulley, over which the saw runs and by which the saw issuspended, means for imparting rotary motion to 'the pulley, alowerfl'ght-reversing pulley about which the saw runs and which isSuspended entirely by the saw, means for causing the flight portions ofthe saw intermediate of the pulleys to travel in sliding surfacecontact, a support, and a jointed arm structure swingingly attached atone end to the support and from the other end o! which theupper pulleyis Suspended.

8. The structure of claim 7 characterized by the provision of 'a swivelconnection between the upper pulley and the end of the jointed armstructure.

9. The structure of claim 'I characterized by the provision oi' aJointed arm structure comprising a bracket from the outer end of whichthe upper pulley is Suspended and a member to which the bracket ishingedly attached and which is hingedly connected to the support.

10. In a, portable band saw mechanism, the combination of a supportadapted to be mounte'd on a supporting surface such as the work-piece tobe sawed, a jointed arm structure having one,

combination of a support adapted to be mounted on a supporting 'surfacesuch as the work-piece to be sawed, a suction grip base for the supportarranged to maintain the support in position on the supporting surface,a jointed arm structure having one end hingedly connected to the supecut a single kerf.

&416.877

port, en upper night-:evening puuey suspended from the other end of thejointed arm structure, means ior impartingrotry motion to said pulley, aband 'saw running over said 'puney and suspended therefom, a, secondflight-reversing pulley about'which the saw runs and which is suspendedentirely by the saw, and means Ior causing the flight'portions 'of thesaw intermediate of the pulleys to travel in sliding surface contact to12.- The structure of claim 10 eharacterizedby the provision of a.swivel connection between the jointed arm structure nd `t'he -flrstmentioned The following referencs` are 'ohricil in .the

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